The invention relates to electronic communications and, more particularly, to external protocol hooks for accomplishing communication between units in a digital communications system.
In electronic communications between units within a communications system, units are able to communicate each with the other because they follow particular protocols for communicating signals within the system. These protocols must provide for compatibility of communication operations between units in order to enable appropriate communications. In general, protocols for communications between units have been specific to the particular units and the particular electrical design of the units. Because of this specific nature of protocols for particular units, the prior designs for units have had only limited, if any, application versatility.
It has previously been particularly difficult for electronic communications designers to develop designs for communications units that may be employed in a variety of different applications. This has been the case, at least to some extent, because of the external protocols followed by communications units operating in accordance with the prior designs. System components of the prior communications units have typically been chosen according to the designs necessary for the communications units to operate according to system-specific external protocols. The particular external protocols followed within each system have, therefore, typically been system specific and, thus, suitable only for communications between units of the particular system for which the units are designed. It would be an improvement and advantage to provide electronic communications units capable of communicating via a variety of external protocols in systems and applications.
In regard to communications between electronic communications units, the term "hooks" is used to identify the particular means by which the units appropriately interface via external protocols to enable appropriate communications between units. Various external protocol hooks for accomplishing communications between units of a communications system have been employed in the past. An example of hook methodology for enabling communications between normally asynchronous units (i.e., each unit having its own independent internal clock) has been to make the timing of one unit, the slave, react in accordance with the timing of the other unit, the master.
Typically, the slave unit utilizes a phase lock loop and jitter integrator of the slave unit to slave that slave unit's timing to the timing of the master unit. The phase lock loop of the slave unit tracks the master unit's communication's signal timing frequency up and down, that is, by increasing and decreasing the frequency of the slave unit's clock signal, in order to seek to maintain a lock on those signals and their timing. The jitter integrator of the slave unit serves to adjust the frequency of the clock at the slave unit based on the operation of the phase lock loop to compensate for jitter. The jitter integrator may accomplish this adjustment, for example, by dictating a frequency divisor value used to create the slave clock, depending upon the adjustment in the slave unit timing necessary at any instant to maintain that timing as slave to the master unit timing.
Embodiments of the present invention provide a novel system and method of external protocol hooks, which system and method enable communications between units of an electronic communications system. In particular, the system and method provides an interface port that allows connection with a wide variety of communication protocols. Thus, the system and method are not system-specific and so have application to communications systems employing varied external protocols. The invention is, thus, a significant improvement and advance in the art and technology.